And I spoke to Kurt Campbell, who's a top Pentagon official during the 1990s, and he said there are actually ways around that as well.

NPR: U.S., Iraq Ponder Long-Term Treaty

The top US East Asia diplomat, Kurt Campbell, is due in Japan later in the week for talks expected to include the territorial row, on which Washington has urged both sides to exercise caution.

BBC: China 'to survey disputed East China Sea islands'

In Washington the three officials, America's top diplomat on Asia Kurt Campbell, South Korea's nuclear envoy Lim Sung-nam and Japan's representative to the six-party talks Shinsuke Sugiyama, said they were committed to the denuclearisation deal.

BBC: 'Path open' for North Korea talks, neighbours say

Kurt Campbell, the former top U.S. diplomat for Asia, told reporters at a forum in Seoul that there was substantial concern with the way Pyongyang has treated what was supposed to be a venue to improve inter-Korean relations.

NPR: Most South Koreans Leave North Korean Factory